Combined exhaust manifold and muffler



Feb. 20, 1934. I c, E, HATHORN 1,947,987

COMBINED EXHAUST MANIFOLD AND MUFFLER Filed March 26, 1929 3 Sheets-Sheet l ATTORNEY Feb. 20, 1934. c HATHORN 1,947,987

COMBINED EXHAUST MANIFOLD AND MUFFLER Filed March 26, 1929 3 Sheets-Sheet 2 lNVENTOR ATTORNEY Y CHARLES fiHATuoRn.

Patented Feb. 20, 1934 UNITED STATES PATENT OFFICE COMBINED EXHAUST MANIFOLD AND MUFFLER Application March 26, 1929. Serial No. 349,954

"lClalms.

My invention relates to multi-cylinder internal combustion engines and more particularly to means for manifolding and at the same time silencing or muflling the engine exhaust. It has been the practice heretofore, in internal combustion engines, and especially in the internal combustion engines of aircraft, to manifold the exhaust, and thereafter by means of a suitable muiller or silencer, muiiie the exhaust; said manifold and mufiler being so relatively arranged and so related to the engine cylinders as to admit of the passage of the products of combustion from said cylinders into said manifold, and from said manifold, either directly or indirectly, into said muffler, each said part being separately designed, separately formed and separately fastened either to the engine or to the aircraft within which the engine is installed.

The principal object of the present invention is to provide in lieu of said separately formed parts, a unit or combination structure, i. e., a combined manifold and mufller in which the products of combustion are manifolded and muilled without being separately circulated first thru the one and then thru the other said part or structure. In other words, instead of two flight resistant masses, each performing its separate and independent function, a unit mass is provided, said unit mass or structure being so formed and constructed as to completely and satisfactorily perform the separate functions heretofore performed by the two said separate parts.

Other objects and advantages of the invention will be hereinafter more fully disclosed.

In the drawings, wherein like reference characters denote like or corresponding parts,

Fig. 1 is an elevation of that form of combined manifold and mufller designed for use on a six cylinder radial cylinder internal combustion 40 engine;

Fig. 2 is an edge view of one of the device parts illustrated in Fig. 1;

Fig. 3 is a longitudinal vertical sectional view of that part of the combination device illustrated in Fig. 2;

Fig. 4 is a similar view,'the section being taken at substantially a right angle to that of Fig. 3;

Fig. 5 is a section on the line 55 of Fig. 3;

Fig. 6 is a side elevation, partly broken away, of that form of combination manifold and muiiler designed for use on or in connection with an in line" multi-cylinder engine;

Fig. 7 is a longitudinal sectional view of the structure illustrated in Fig. 6, and

Fig. 8 is a section on the line 8-8 of Fig. 7.

parts 10 respectively serve.

In Figs. 1 to 5, inclusive, the combined manifold and muiiler selected for illustration is shown as comprising two parts or devices 10. Said parts 10 are preferably of substantially semi-circular form and are provided, each with a plurality of exhaust inlets 11 by means of which the separate device parts are directly fastened to the multiple cylinders of a radial cylinder internal combustion engine. As indicated in said Fig. 1, the number of exhaust pipes 11 preferably corresponds with the number of cylinders which the said device As illustrated in Figs. 3 and 4 each said device part 10 comprises an outer manifold shell 11, an intermediate shell 12 and an inner shell 13, each said shell being substantially cylindrical and the total number of shells being of progressively larger diameter from the inner shell 13 to the outer shell 11'. Said outer shell 11, for the purpose of taking care of the expansion and contraction due to temperature changes, comprises two or more shell sections 14 held together bysuitable bands 15 arranged to encircle the respective joints. As clearly shown in Fig. 1 each of the exhaust pipes 11 is provided with a flange, each of the flanges having bolt holes formed therein. By means of bolts inserted through these holes the exhaust pipes 11 are secured directly to the engine. Therefore, it is impossible for any one of the sections 14 to move as a unit with reference to the engine and is impossible for the manifold sections 14 to be blown apart by the blast of the exhaust gases, even though the separate sections 14 are merely joined to each other telescopically by means of the bands 15. At one end the outer shell 11 is completely closed as at 16 whereas at its opposite end it is flanged inwardly as at 17 and has welded or in some other manner fastened thereto the intermediate shell 12. Said intermediate shell and said inner shell together constitute an elongated muiiier or silencer, whereas the outer shell 11 will be hereinafter referred to as the manifold. The mufller or silencer is enclosed for the major part within the manifold and is carried at its inner end to a point in more or less close proximity to the closed end 16 of the outer shell. Since said muffler or silencer is fastened to the flange 17 at the opposite end of the manifold, obviously the products of combustion entering the shell find their only outlet to the outside atmosphere by way of the muiller.

From its point of attachment to the flange 1'7 the intermediate shell 12 is carried throughout substantially the full length of the manifold and at its opposite end is inturned as at 18 to provide an annular support for the inner shell 13 of the muffler. Said intermediate shell 12 is imperforate and the exhaust upon entering the manifold is directed around said intermediate shell and toward the closed end 16 of the manifold. The inner shell 13 extends substantially throughout the full length of the manifold and is fastened at one end to said inturned flange 18. Throughout its length said inner shell is suitably perforated as at 19 in order that the products of combustion entering thereinto at the closed end of the manifold may be directed alternately from within said inner shell into the space between it and the intermediate shell, suitable baffles 20 mounted within the irmer shell serving as deflectors. Ultimately the products of combustion find their way to and thru the outlet end of the muffler.

To take care of expansion and contraction of the inner and intermediate shells, the inner shell, at intervals of space throughout its length, is held concentric to the intermediate shell by means of supports 21 fastened thereto and bearing on but in no way directly fastened to the intermediate shell. A similar support 22, in the nature of a spider, acts to center the intermediate shell with respect to the outer shell or manifold. Like the supports 21, the spider 22 has no direct connection with the intermediate shell. It will be seen, therefore, that both the inner shell and the intermediate shell may move axially or longitudinally as expansion and contraction of the metal occurs.

In the modification of Figs. 6 to 8, inclusive, a similar form of device is illustrated. This latter device, however, instead of being either circular or semi-circular, is unbent since it is intended to be usedas a combined manifold and muiller for in line multi-cylinder engines. Except for its shape, the structure illustrated in Figs. 6 to 8, inclusive, is identical with the structure designed for use on a radial cylinder engine, and the same reference numerals therefore apply.

A combined manifold and muffler thus characterized is especially adapted to the aircraft engine. Being a unit structure its resistance as compared to prior separate devices is substantially less. The products of combustion are effectively manifolded and properly muilled prior to the passage thereof to the outside air. By distributing the inlet openings longitudinally of the manifold the exhaust is directedv against the outer face or surface of the intermediate shell, and since the only outlet to the manifold is by way of the mufliler, obviously the exhaust must find its way to the outside atmosphere by its passage first from the inlet end of the muffler, thence alternately back and forth from the inner to the intermediate shell until finally the outlet end of the mufller is approached. At said outlet end, if desired, the inner shell may be shaped as indicated in Figs. 3 and 7 to produce in effect a venturi action. Moreover, thru a slight modification in the form of the manifold and the muliler enclosed therein, the combination structure may be used with any and all types of internal combustion engines.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What I claim is:

1. In combination, a manifold for the exhaust of a multl-cylinder internal combustion engine comprising a tubular shell having a plurality of lateral inlets for the entrance of exhaust gases from the engine and allowing the mingling of those gases within said shell, said shell being closed at one end and provided at its opposite end with an inturned flange, a. muiller enclosed within and extending lengthwise of said shell and thru which the exhaust is passed in its passage to the outside atmosphere, said muffler being supported at one end and providing at the flanged end of said shell a closure therefor by its engagement with said flange, and a support for the opposite end of said muflier carried by said shell and with respectto which said muiller is axially movable.

,2. In combination, a manifold for the exhaust of a multi-cylinder internal combustion engine having longitudinally distributed exhaust inlet openings formed therein, said manifold at one end being completely closed, a muffler enclosed within and extending lengthwise of said manifold and thru which the exhaust is passed in its passage to the outside atmosphere, said muiiier being rigidly supported by and providing at the opposite end of said manifold a closure against the passage of the exhaust therefrom, and a non-fixed support for said muffler carried by and enclosed within said manifold in spaced relation to said rigid support.

3. In combination, a manifold for the exhaust of a multi-cylinder internal combustion engine comprising a tubular shell having a plurality of longitudinally distributed lateral exhaust inlet openings for the entrance of exhaust gases from the engine and allowing the mingling of those gases within said shell, a muffler of substantially less cross-sectional area enclosed within and extending lengthwise of said shell and thru which the exhaust is passed in its passage to the outside atmosphere, said muffler comprising an imperforate outer shell and a perforated inner shell, the exhaust gas being directed to pass through said perforate inner shell, then to impinge and follow along'said imperforate shell and to pass again through said perforate shell, and a support for said muiiier carried by and within said first mentioned shell.

4. A combined exhaust manifold and muffler comprising an outer shell, an intermediate shell, and an inner shell between which the exhaust is passed in its passage thru said structure, passages being provided between the outer shell and the inner shell and between the inner shell and the intermediate shell and supports carried by certain of said shells and bearing on adjacent shells for holding said shells in spaced relation, said supports in each instance, being fastened to but one of said shells whereby adjacent shells are free to move axially with respect to each other.

5. A mufller comprising an outer tube, an intermediate concentric tube joined to one end of the outer tube but not to the other and an inner concentric tube joined to the opposite end of the intermediate tube from that to which the outer tube is joined and not otherwise joined to the outer tube or to the intermediate tube whereby substantially free expansion and contraction of the tubes and movement relative to each other on account of said expansion and contraction is allowed, the inner tube being open at its end at its joint with the intermediate tube and both the inner tube and the intermediate tube being spaced at the adjacent end of the outer longitudinally from the outer tube whereby a passage is provided for from the outer tube to the inner tube.

6. A combined exhaust manifold and muiiler comprising an outer tubular shell having a plurality of longitudinally distributed lateral exhaust inlet openings formed therein for the entrance of exhaust gases from the engine and allowing the mingling of those gases within said shell and having one end completely closed and the other end open, an annular support secured within said shell adjacent to the end thereof opposite to the said closed end, an intermediate shell secured within said annular support-and extending within said outer shell toward the closed end thereof to a point adjacent to but not contacting with said closed end and said in-' termedlate shell having an inturned flange at said point, an inner shell secured to and within said inturned flange and extending within said intermediate shell away-from the closed end of said outer shell whereby discharged into said outer shell must pass through portions of said outer shell, said intennediate shell and said inner shell before escaping to the open airv through the open end'of said outer shell.

'I. A combined exhaust manifold and muiiler comprising three concentric shells, the outer shell being open at one end to the inner shell, the inner shell being open at its opposite" end to allow gases to pass out, and the inner shell being perforated to allow passage of gases between it and the intermediate shell; a plurality of stops inserted within the inner shell for compelling gases passing longitudinally of the muifler to pass from the inner shell to the intermediate shell; and annular stops provided in the intermediate shell to compel gases passing longitudinally of the muiller to flow from the intermediate shell to the inner shell. 1

, CHARLES E. HATHQRN. 

